Method for preparing simple tertiary thenylamines



Patented July 3, 1951 METHOD FOR PREPARING SIMPLE TERTIARY THENYLAMINES Howard D. Hartough, Pitman,

and Sigmund J.

Lukasiewicz, Woodbury, N. J., assignors to Socony-Vacuum Oil Com corporation of New York N '0 Drawing. Application April 9, 1947, Serial No. 740,494

8 Claims. 1

The present invention relates to the preparation of simple tertiary thenylamines and, more particularly, to the products obtained by reacting formaldehyde or its polymers, ammonium chloride and a thiophene derivative in which one of the alpha carbons is blocked.

In application Serial No. 636,511 filed December 21, 1945, in the names of Howard D. Hartough and Sigmund J. Lukasiewicz, now abandoned, a method for producing thenylamines (aminomethylthiophenes), sub-resinous bodies, and resinous bodies, was described. In general, this procedure involved reaction of thiophene or alkylthiophenes or halothiophenes or alkoxythiophones and the like or, in general, compounds having an unsubstituted thiophene nucleus or compounds having stable electro-positive substituents other than unstable (OH) and (NI-I2) groups attached to the thiophene nucleus, formaldehyde or its polymers, and ammonium halide or amine salts. It was pointed out therein that the primary and secondary amines, WCH2NH2HX and WzNHHX, respectively, Where W is one of the group thiophene and thiophenes having stable electro-positive substituent groups attached to the nucleus, can be isolated in pure state by distillation in vacuum. It was also pointed out that the simple tertiary amine had not been obtained and, in fact, a complex amine having chemical properties indicative of a polymeric amine structure containing several units of the hand, when it is desired to obtain substituted tertiary thenylamines, the substituted thiophene pany, Incorporated, a

is employed and the substituent group not replaced.

The following non-limiting examples are illustrative of the production of simple tertiary thenylamines and of simple substituted tertiary thenylamines.

Example I A mixture of about 196 parts by weight of 2- methylthiophene (about 2 moles) and about 161 parts by weight of ammonium chloride (about 3 moles) is prepared and thoroughly agitated. To the well agitated mixture is added about 162 parts by weight of an aqueous solution of formaldehyde containing about 36 per cent by weight of formaldehyde (about 2 moles). After the addition of all of the formaldehyde solution, the mixture is warmed gently until the reaction is initiated and the reaction temperature allowed to rise and kept at about to about degrees centigrade. The reaction temperature is controlled within the aforesaid limits by the use of indirect cooling, if necessary. When the temperature of the reaction begins to decrease the mixture is heated to reflux and kept at that temperature. for about 30 minutes. Thereafter, the reaction mixture is cooled to ambient temperatures, a solvent such as benzene added, and the reaction mixture neutralized with alkali, preferably an aqueous 40 per cent sodium hydroxide solution. The solvent layer is separated from the aqueous layer and the aqueous layer extracted one or more times with solvent. The extracts are combined and the solvent removed by distillation. The still residue is then subjected to fractionation under a reduced pressure to yield the following prodnets in the amounts indicated: 5-methylthenylamine, 21 parts by weight, boiling point 68-69 degrees centigrade at l millimeters of mercury; di-(5-methyl-2-thienyl)methane, boiling point -136 degrees centigrade at 4 millimeters, 21 parts by weight; di-(5-methyl-2-thenyl) amine, boiling point 161-162 degree centigrade at 4 millimeters, 39 parts by weight; tri-(5-methyl-2- 'thenyDamine, boiling point 207-214 degrees centigrade at 3 millimeters, melting point 81-815 degrees centigrade, 32 parts by weight; and 83 parts by weight of a residue. Extraction of the residue with boiling alcohol yields an additional .10 parts by Weight of tri-(5-methyl-2-thenyl)- amine.

5-methyl-2-thenylamine Di- 5-methyl-2-thenyl) amine Tri- (5-methyl-2-theuyl) amine 4 to cool the reaction mixture but agitation of the reaction mixture was continued for an additional hour and a half. After cooling the reaction mixture to about degrees centigrade the mixture m 5 was filtered, the precipitate washed with benzene and recrystallized from about 6,000 parts by weight of water to yield 379 parts by weight of di- (5-methyl-2-thenyl) amine hydrochloride having a melting point of 216 to 217 degrees centigrade, with decomposition. This is a yield of I about 56 per cent of theoretical. Upon analysis it was found that the amine hydrochloride contained 23.54 per cent sulfur and 5.36 per cent nitrogen. Calculated sulfur content for an aqueous layer. Upon evaporation of the benzene layer 82 parts by weight of the di- (5-methyl- Z-thienyl) methane were recovered. A water and benzene insoluble oil in the amount of about 66 parts by weight was also obtained but not identi- 5 fied. It contained 16.3 per cent sulfur and 4.1

per cent nitrogen which cannot be reconciled (111) Di (5 methy1 2 thieny1)methane with any simple am ne structure. lieutralizat on of the water layer with aqueous sodium hydroxide J H followed by extraction thereof with benzene Hac a or!3 yielded 15 parts by weight of 5-methyl-2-thenyl- S H 3 (IV) amine and about 109 parts by weight of a light These products were analyzed as follows, red viscous oil having a sulfur content of 22.98 per Calculated Found (I) S-methyI-Z-thenylamine(C5HgN)as N-(fi-methyl -2-thenyl) -N -phenyl- Per cent Per cent thiourea (C'H MN2S2) Nitrogen 0 69 10.45 (II) [di (5-methyl-2-thenyl) amine] OuEmNS: Sulfur. 27. 00 27. 03 Nitrogen" 5. 91 5. 98 (III) [tri- (S-methyl-Z-thenyl) amine] CmHzyNSg Sulfur-l... 27. as 27. 73 Nitrogen. 4. 01 4. 04 (IV) cli-(5-methyl-2-thienyl)methane 011E138) Sl1lfl1l 30. 7 30. 4

The 5-methyl-2-thenylamine absorbed carbon dioxide from the air too rapidly to obtain accurate analysis. Therefore, the N-(S-methyl- 2-thenyl)-N'-phenylthiourea was prepared in order to identify this material. The phenylthiourea compound melted at 133-134 degrees centigrade and contained 10.45 per cent nitrogen. While the di-(5-methyl-2-thenyl)amine appeared to form a thiourea derivative with phenylisothiocyanate, no crystalline product could be obtained.

Example II A mixture of about 490 parts by weight of Z-methylthiophene (about 5 moles) and about 535 parts by weight of ammonium chloride (about 5 moles) was prepared. The mixture was thoroughly agitated and during agitation about 425 parts by weight of an aqueous solution of formaldehyde containing 36 per cent formaldehyde (about 5 moles) was added. After the addition of all of the formalin solution the mixture was warmed to 40 degrees centigrade, at which temperature the reaction was initiated. The temperature of the reaction was controlled between about 60 to 70 degrees centigrade by means of an ice bath. Shortly after the reaction was initiated crystals began to form and within a short time a slurry developed which made stirring difficult. After about 30 minutes it was no longer necessary calculated sulfur cent; a nitrogen content of 7.87 per cent; and a hydroxyl number of 481.

Example I l I A mixture of about 276 parts by weight of 2-tbutylthiophene (about 2 moles) and about 161.5 parts by weight of ammonium chloride (about 3 moles) was heated to about '75 degrees centigrade and about 84 parts by weight of an aqueous solution of formaldehyde containing about 36 per cent formaldehyde (about 1 mole) were added during a period of about 30 minutes. Thereafter the mixture was heated at about 85 to about degrees centigrade for one hour, the reaction mixture cooled to ambient temperatures and the organic layer separated from the aqueous layer. The organic layer was diluted with petroleum ether and about 14 parts by weight of tri-(5-tbutyI-Z-thenyl)amine hydrochloride separated out. The tertiary'amine hydrochloride was recrystallized from alcohol and had a melting point from 204 to 206 degrees centigrade with decomposition. Distillation of the filtrate permitted recovery of unreacted 2-t-butylthiophene and yielded an additional 44 parts by weight of tri- (5-t-butyl-2-thenyl)amine hydrochloride as a residue. On analysis of the amine hydrochloride it was found to have a sulfur content of 19.20 per cent and. a nitrogen content of 2.81 per cent. The content of the compound C27H40C1NS3 is 18.94 per cent and the calculated nitrogen content is 2.83 per cent.

Neutralization of the water layer with 40 per cent aqueous sodium hydroxide solution followed by extraction with benzene yielded 4.5 parts by weight of a light yellow oil having a sulfur content of 15.9 per cent and a nitrogen content of 8.5 per cent.

The present application is a continuation-inpart of our earlier filed application Serial No; 636,511, filed December 21, 1945.

We claim:

1. A method for producing tri-(5-alkyl-2- thenyl) amine which comprises mixing 2-alkylthiophene, formaldehyde and an amount of ammonium halide having a molecular weight greater than 38 in excess of the molal equivalent of said 2-a1kylthiophene holding the mixture at temperatures not greater than reflux to obtain a reaction mixture containing tri-(5-alkyl-2-thenyl) amine hydrohalide, separating said tri-(5-alkyl- 2-thenyl) amine hydrchalide from said reaction mixture and recovering tri-(5-alkyl-2-thenyl) amine.

2. A method for preparing simple tertiary thenylamines as set forth and described in claim 1 in which the reaction temperature is about 80 to about 90 C.

3. A method for preparing tri-(5-methyl-2- thenyl) amine which comprises mixing Z-methylthiophene, an amount in excess of the molal equivalent of said methylthiophene of ammonium halide having a molecular weight in excess of 38 and formaldehyde to form a reaction mixture, heating said reaction mixture to about 80 to about 90 C., cooling said reaction mixture to ambient temperature, neutralizing said reaction mixture with aqueous metal hydroxide, extracting said neutralized solution with a solvent for thenylamines, removing said solvent, and recovering tri-(5-methyl-2-thenyl) amine.

4. A method for preparing tri-(5-tertiarybutyl- Z-thenyl) amine which comprises mixing 2- tertiarybutylthiophene, formaldehyde and an amount of ammonium halide having a molecular weight greater than 38 in excess of the mclal equivalent of said tertiarybutylthiophene to form a reaction miXtLu'e holding said reaction mixture at about 85 to about 90 C., and recovering tri- 5-tertiarybutyl-2-thenyl) amine.

5. A method of preparing simple tertiary thenylamines which comprises mixing (A) mm.

phone having 1 to 3 substituent groups only one of said substituent groups being attached to an alpha nuclear carbon atom and said substituent groups being selected from the group consisting of alkyl, alkoXy and halogen, (B) one of the group consisting of formaldehyde and reversible polymers of formaldehyde and (C) more than a molar equivalent based upon the amount of said thiophene of an ammonium halide and holding said mixture at a temperature not greater than reflux.

6. A method of preparing simple tertiary thenylamines which comprises mixing (A) a mono-substituted thiophene, said substituent being selected from the group consisting of alkyl, alkoxy and halogens and being attached to an alpha nuclear carbon atom, (B) formaldehyde and (C) an amount of ammonium chloride in excess of the molar equivalent of said thiophene, and holding said mixture at a temperature not greater than reflux.

'7. A method of preparing simple tertiary thenylamines which comprises mixing (A) thiophene having 1 to 3 substituent groups onl one of said substituent groups being attached to an alpha nuclear carbon atom and said substituent group being selected from the group consisting of alkyl, alkoxy and halogens, (B) one of the group consisting of formaldehyde and reversible polymers of formaldehyde and (C) an amount of ammonium chloride in excess of the molar equivalent of said thiophene, and holding said mixture at a temperature not greater than reflux.

8. The method of preparing simple tertiary thenylamines as set forth and described in claim '7 wherein the reaction temperature is about C. to about C.

HOWARD D. HARTOUGH. SIGMUND J. LUKASIEWICZ.

REFERENCES CITED The following references are of record in the file of this patent:

vol. 1, pp. 304 and 

5. A METHOD OF PREPARING SIMPLE TERTIARY THENYLAMINES WHICH COMPRISES MIXING (A) THIOPHENE HAVING 1 TO 3 SUBSTITUENT GROUPS ONLY ONE OF SAID SUBSTITUTENT GROUPS BEING ATTACHED TO AN ALPHA NUCLEAR CARBON ATOM AND SAID SUBSTITUENT GROUPS BEING SELECTED FROM THE GROUP CONSISTING OF ALKYL, ALKOXY AND HALOGEN, (B) ONE OF THE GROUP CONSISTING OF FORMALDEHYDE AND REVERSIBLE POLYMERS OF FORMALDEHYDE AND (C) MORE THAN A MOLAR EQUIVALENT BASED UPON THE AMOUNT OF SAID THIOPHENE OF AN AMMONIUM HALIDE AND HOLDING SAID MIXTURE AT A TEMPERATURE NOT GREATER THAN REFLUX. 